Pulp and Paper Industry Distributed Control System (DCS) Solution

Pulp grinders, hydraulic pulpers, and pressure screens are widely used in papermaking pulping equipment. However, most existing systems suffer from low efficiency, high failure rates, and limited automation. Taking a typical pulper system as an example: the original setup uses three-phase AC asynchronous motors with direct-on-line (DOL) starting at line frequency. This results in low motor efficiency and power factor, failing to meet the latest national energy efficiency standards. The system operates long-term in the 40%~60% load range, which corresponds to the low-efficiency zone of asynchronous motors, accompanied by excessive noise and vibration. Addressing the specific characteristics of pulping and papermaking equipment, this solution establishes a four-layer drive and control architecture: Information Layer, Control Layer, Drive Layer, and Execution Layer. - **Information Layer**: Comprises cloud platforms, mobile apps, and data acquisition I/O for real-time data visualization and early warning capabilities. - **Control Layer**: Managed by PLCs for centralized control and speed regulation. - **Drive Layer**: Utilizes WD200 series high-performance vector inverters and ECC electrical cabinets. - **Execution Layer**: Employs TYCP5 series low-speed permanent magnet synchronous motors (PMSM) and WEPM series PMSMs. The TYCP5 series low-speed PMSM is built on core technologies of permanent magnet drive and high energy efficiency. It is ideal for low-speed, high-torque mechanical equipment requiring variable speed control in the paper industry, such as pulp grinders, pulpers, screeners, and agitators. Specifications include rated power of 1.1~900kW, rated voltage of 380V, rated speed of 25~500r/min, achieving 1 class energy efficiency, frame sizes from 180 to 560, and V1 mounting configuration. The WEPM series PMSM meets IE5~IE4 efficiency standards. Featuring rotors with permanent magnets, these motors offer higher efficiency and power density than induction motors, resulting in smaller frame sizes for the same power and torque output. Designed with self-cooling, they operate efficiently under inverter drive without forced ventilation, delivering excellent constant torque performance at low speeds and a wide speed range. All frame sizes maintain installation dimensions consistent with induction motors, complying with IEC and national standards for easy installation. Compared to equivalent IE3 induction motors, the volume is reduced by 1~2 frame sizes, the constant torque speed range is wider, noise reduction reaches up to 15dB(A), and the elimination of reactive excitation current significantly improves the power factor. Additionally, zero rotor loss and reduced losses in other components enhance overall performance. The WD200 series high-performance vector inverter features advanced motor control algorithms compatible with both asynchronous and permanent magnet synchronous motors. It covers power ranges from 0.75~1000kW and supports multiple power supply types: single-phase 200V~240V, three-phase 200V~240V, three-phase 380V~480V, and three-phase 660V~690V. Its compact book-style design ensures a small footprint and easy cabinet integration, with simplified internal layouts for convenient wiring. Users can switch between asynchronous and synchronous motor modes via parameter settings to achieve wide-range speed control with high torque. Controlled rectification technology minimizes system failures, while comprehensive protection functions reduce hardware damage risks. The inverter automatically acquires motor parameters for simple setup and debugging. It offers various panel options, rich status information, and supports RS485 interfaces or fieldbus protocols for data exchange. **Typical Retrofit Case 1:** A 160kW pulper originally equipped with a Y2-355M-6 three-phase asynchronous motor (160kW, 400V, 277.7A, 50Hz, 985rpm, cosφ0.88) operated with DOL starting. Efficiency was 87.50% in the 40%~60% load range and 94.00% in the 60%~160% load range. Considering cost and retrofit feasibility, the upgraded system now uses a WD200 high-performance vector inverter to drive a 160kW WEPM5 PMSM. System efficiency improved by 15%, motor noise decreased by 15dB, heavy-load starting stability increased with minimal grid impact, and enhanced inverter protection significantly reduces equipment damage caused by external factors. **Typical Retrofit Case 2:** A 250kW pulper originally driven by a three-phase AC asynchronous motor with DOL starting experienced current fluctuations between 40% and 90%, indicating high actual load rates. The retrofit replaced the original motor + gearbox transmission with a WD200 high-performance vector inverter driving a TYCP5-400L-250-530 low-speed PMSM (rated speed 530rpm). Efficiency reached 95.8% in the 40%~60% load range and 96.1% in the 60%~160% load range. System efficiency increased by 25%. Eliminating the gearbox resulted in near-zero maintenance requirements and reduced costs. Removing redundant transmission components significantly reduced the footprint, improving space utilization. The system allows speed adjustment based on process needs and includes intelligent features such as visual monitoring and early warnings.

Use Cases:Low-speed, high-torque equipment for the pulping and papermaking industry: refiners, hydraulic pulpers, pressure screens, screening machines, and mixers.